Escherichia coli ItaT is a type II toxin that inhibits translation by acetylating isoleucyl-tRNAIle

Brendan Wilcox, Ilya Osterman, Marina Serebryakova, Dmitry Lukyanov, Ekaterina Komarova, Bridget Gollan, Natalia Morozova, Yuri I. Wolf, Kira S. Makarova, Sophie Helaine, Petr Sergiev, Svetlana Dubiley, Sergei Borukhov, Konstantin Severinov

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

Prokaryotic toxin-antitoxin (TA) modules are highly abundant and are involved in stress response and drug tolerance. The most common type II TA modules consist of two interacting proteins. The type II toxins are diverse enzymes targeting various essential intracellular targets. The antitoxin binds to cognate toxin and inhibits its function. Recently, TA modules whose toxins are GNAT-family acetyltransferases were described. For two such systems, the target of acetylation was shown to be aminoacyltRNA: the TacT toxin targets aminoacylated elongator tRNAs, while AtaT targets the amino acid moiety of initiating tRNAMet. We show that the itaRT gene pair from Escherichia coli encodes a TA module with acetyltransferase toxin ItaT that specifically and exclusively acetylates Ile-tRNAIle thereby blocking translation and inhibiting cell growth. ItaT forms a tight complex with the ItaR antitoxin, which represses the transcription of itaRT operon. A comprehensive bioinformatics survey of GNAT acetyltransferases reveals that enzymes encoded by validated or putative TA modules are common and form a distinct branch of the GNAT family tree. We speculate that further functional analysis of such TA modules will result in identification of enzymes capable of specifically targeting many, perhaps all, aminoacyl tRNAs.

Original languageEnglish (US)
Pages (from-to)7873-7885
Number of pages13
JournalNucleic acids research
Volume46
Issue number15
DOIs
StatePublished - Sep 6 2018

All Science Journal Classification (ASJC) codes

  • Genetics

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